console.log([1, 2, 3].map(x => x * x));

class Calc {
	constructor() {
		console.log('Calc constructor');
	}

	add(a, b) {
		return a + b;
	}
}

var c = new Calc();
console.log(c.add(3,5));

import React from "react";
import { render } from "react-dom";

class Test extends React.Component {
	render() {
		return <div className={this.props.className}>Hello {this.props.name}</div>;
	}
}

window.addEventListener('DOMContentLoaded', function() {
	render(<Test className="hello" name="Leray"/>, document.getElementById('app'));
}, false);